This invention relates to improvements in systems for processing and editing sequences of frames of video signals.
When editing video signal sequences the position of the point of editing is often dependent on the timing of the accompanying audio. For example in the case of video accompanied by speech it might be desirable to remove part of the speech in which case the video signals associated with that part of the speech may also have to be removed and the position of the editing would then be dependent on, say, the end of a sentence. Most existing editing systems have the capability of displaying sequences of frames of video signals in both forward or reverse order for example where a video tape is played backwards. In the editing system manufactured by the U.K. company Quantel Limited and identified by the tradename "Harry" the video signals are recorded on parallel transfer discs and the operator controls the reading of the store so that the sequence of frames may be displayed in reverse or usual order at the speed required. A processor is also provided which allows the signals to be processed as required. Using conventional audio techniques in these editing systems the operator is limited because, when the frames are displayed in reverse order, the audio is also played in reverse. This is particularly disadvantageous when speech is accompanying the video as the words will be reversed and it is therefore more difficult to identify the position where an edit is required.